Convertible ski-supported vehicle

ABSTRACT

Universal wheel unit for mounting one or more wheels on the ski of a snowmobile. The wheel unit is a separate assembly that is detachably mountable on the ski or is an integral component of the ski. When retrofitting skis, the wheel unit is mountable on the kingping, on the side wall, or on the saddle. Wheels are readily deployable or retractable as ground surface conditions require, and allow the snowmobile to be driven over gravel, dirt, and hardtop surfaces, while maintaining steerability with the handlebars.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.10/352,302, filed on Jan. 27, 2003, now U.S. Pat. No. 6,824,147 B2,which was a Continuation-In-Part (CIP) Application of U.S. patentapplication Ser. No. 10/233,718, filed on Sep. 03, 2002, now abandoned,and a Continuation-In-Part (CIP) of U.S. patent application Ser. No.09/818,058, filed on Mar. 26, 2001, now U.S. Pat. No. 6,527,282.

BACKGROUND INFORMATION

1. Field of the Invention

The invention relates to the field of ski-supported vehicles. Moreparticularly, the invention relates to snowmobiles equipped with wheelsthat will allow the snowmobile to travel readily over surfaces notcovered with snow or ice.

2. Description of the Prior Art

Snowmobiles are vehicles that are constructed to travel across snow andice. As is generally known, the snowmobile is driven by an endless drivetrack arranged at the rear end of the underside of the snowmobile. Thefront end of the snowmobile is supported and rides along two skis, whichglide across the surface of the snow or ice. The skis typically have acarbide runner that runs along a portion of the bottom surface of theski, to help keep the snowmobile traveling along a smooth track.

A disadvantage of snowmobiles is that the skis don't readily glideacross gravel, hardtop, or other non-snow surfaces. This makes itdifficult, if not impossible, to steer a snowmobile because the skis donot respond properly to the steering operations initiated at thehandlebars. Quite often, the snowmobile needs to be dragged or pushed indriveways and across roadways, etc. Furthermore, when a snowmobile isdriven or dragged across a non-snow surface, the carbide runners on theskis are subject to excessive wear and must be replaced more frequently,depending on how often a snowmobile travels across a non-snow surface.This inability to steer snowmobiles on surfaces other than snow and icemakes it difficult for people to maneuver their snowmobiles acrossroadways, driveways, onto ferries, etc.

In recent years, the sport of snowmobiling has changed evolved from oneof traveling relatively short distances over trails close to home to oneof weekend-long or longer cross-country trips. Previously, for example,a snowmobile operator would fill the gasoline tank of the snowmobile inhis or her backyard, transport the snowmobile to a trail site or departdirectly from the backyard for an afternoon or day of travel oversnowmobile club trails, and then return home. Nowadays, people aretraveling great distances across country on snowmobiles that involvetwo- or three-day tours or even such mammoth tours as from Alaska toMaine.

This development of the sport of snowmobiling into extended trips meansthat snowmobiles must now be refilled with gasoline and maintained whilethey are out traveling across open country. Thus, where in the past thetank on the snowmobile was filled at home or at the point of departurebefore a daylong excursion, snowmobiles now need to be refilled whileout traveling. This means that the snowmobile must be driven to aservice station, typically by traveling some distance along a roadsurface other than snow or ice. Also, now that such lengthy trips arebeing undertaken with snowmobiles, the presence of snow along the entireroute is not guaranteed, and consequently, snowmobiles are beingrequired more and more frequently to travel some distance acrosssurfaces other than snow or ice. Before, when a snowmobile needed to bedragged or pushed only a short distance across a roadway or driveway, orup a ramp onto a ferry, it was possible for a person to do it alone orwith the assistance of a traveling companion. Now, however, with theneed to travel several miles along a roadway to get to a fillingstation, the inability to steer a snowmobile has become a major obstaclein the logistics and the enjoyment of the sport.

Efforts to make snowmobiles mobile on gravel or other surfaces have beenundertaken over the years. Prior art includes conversion kits to replacethe skis with wheels. These conversion kits were intended to replace theskis on a semi-permanent basis, that is, to convert a snowmobile into awheeled vehicle for an extended period of time. Such conversion kitstypically require that the ski be removed in order to mount the wheels,or, if the ski does remain attached to the vehicle, a longer kingpinmust be used to mount the wheels. Thus, each time the wheels are mountedor removed, the kingpin must be replaced with the longer or shorter one,respectively. Both methods of converting the snowmobile to a wheeledvehicle involve a fair amount of work. Thus, such conversion kits arenot generally an acceptable solution to the problem of having to changein relatively quick succession back and forth between a vehicle thatrides on skis and one that rides on wheels, as happens when travelingover gravel or hardtop or other surface other than snow or ice to fillthe gas tank or to load onto a ferry.

What is needed, therefore, are means for quickly converting a vehicleback and forth between one that glides on skis to one that rolls onwheels. What is further needed are such means that do not impair thesteerability of the vehicle. What is yet further needed are such meansthat are easily implemented, without requiring great physical strengthand without requiring the use of tools. What is still yet further neededare such means that are retrofittable on any conventional snowmobileski.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a combination ski-wheelunit that will allow one to convert a ski-supported vehicle quickly andeasily to a wheeled vehicle and back to a ski-supported vehicle, withoutrequiring the use of tools. Another object of the present invention isto provide such a unit that will maintain the steerability of thevehicle, whether on skis or on wheels. A further object is to providesuch a unit that, once installed, can be easily deployed withoutrequiring great physical strength. Still another object is to provide awheel kit with deployable wheels that can be retrofitted onto anyconventional snowmobile ski.

The objects are achieved by providing a road wheel unit having one ormore wheels that is permanently or semi-permanently installed on the skiof a conventional snowmobile so as to provide easily deployable orretractable wheels, as the conditions require. In a retracted position,i.e. the standard snowmobile mode of operation, the wheel is carriedalongside the ski, raised above the gliding surface of the ski. In adeployed position, the wheel is lowered, so that the weight of themachine is supported by the wheel. In this deployed position, the wheelunit holds the ski above the rolling surface of the wheel and allows thesnowmobile to ride on wheels and the conventional endless track at therear end. In the deployed mode, the snowmobile remains readily steerablewith the handlebars, and the carbide runners on the ski surfaces are notsubject to excessive wear. Ideally, the wheel or wheels of the wheelunit are easily detachable from the mounting means, leaving the mountingmeans permanently installed on the vehicle, without impairing thefunctionality of the skis. As mentioned above, a wheel unit has one ormore wheels. Generally, at least one wheel is mounted on each of the twoskis of the snowmobile and, thus, the term “wheels” is generally usedhereinafter, although it is understood that, depending on the type ofwheel unit, only one wheel may be mounted on a ski.

There are various types of conventional skis. Some have a kingpinassembly for linking the ski to the snowmobile; other skis have built-upsidewalls and/or a saddle-shape protrusion extending from the sidewallthat is constructed with sufficient strength and rigidity to support alinking assembly that links the ski to the snowmobile. The scope of theinvention includes a wheel unit that is mountable on the kingpin thatlinks the ski to the snowmobile, as well as a wheel unit that ismountable on the side wall or the saddle of the ski, or onto a mountingblock that is integrated into the side wall construction of the ski. Thewheel unit mountable on the kingpin is hereinafter referred to as thekingpin-mount wheel unit; the unit mountable on the side wall, saddle,or onto a mounting block integrated into the side wall construction isreferred to as the side wall-mount wheel unit; and a unit that ismountable on virtually any type of ski, that is, on a kingpin assembly,on a side wall or saddle is referred to as the universal wheel unit.

Each wheel unit includes one or two wheels and a deployment mechanismthat allows the wheels to be deployed or retracted. When a pair ofwheels is mounted on one ski, i.e., one wheel on each outer side of theski, the deployment mechanism ideally simultaneously deploys the wheelon both sides of the ski.

The deployment mechanism is ideally a relatively simple mechanicalshifting and locking mechanism that allows the operator to easily shiftthe wheel unit between a deployed wheel position and a retracted wheelposition and to securely lock the wheel unit in the respective position.One deployment mechanism that is suitable includes a side rail that isshiftably attached to the wheel unit and a latching mechanism forlatching the wheel unit into a first or deployed position and into asecond or retracted position. For example, a latch is mounted on the skior on the wheel unit and the wheel unit locked into position by catchingthe latch in the first position or in the second position on the rail.The first and second position may be connected by a groove and the latchitself may be a pin that is captured at one end in the groove and isslidably movable into the first position or into the second position,where it is secured against unintentional release.

Another suitable deployment mechanisms for securing the wheel unit hasat least two latch bores, depressions, or latch-receiving assembliesthat are provided on the ski, either on the side wall or on a railattached to the ski or attached to the wheel unit. Each of the latchbores, etc. corresponds to a particular position of the wheel unit.Thus, a first position corresponds to a position state and a secondposition to a retracted position of the wheel unit. A latch that ismounted on the wheel unit is securable in one or the other latch bores.For example, a handle with a spring-loaded button or bar is pivotablyattached to the wheel unit. The wheel unit is secured in the deployed orretracted position by pulling on the handle to release the button fromthe respective latch bore, moving the handle to the desired position andallowing the button or bar to snap into the respective other latch bore.

Generally, the deployment mechanism incorporates a locking mechanism forlocking the wheel unit into position, as described above. It ispossible, however, to provide a separate locking mechanism in the ski toensure that the wheel unit is locked into the respective deployed-wheelor retracted-wheel position. In an embodiment in which two wheels aremounted on a ski, a side rail is pivotably mounted each side of the skiand a yoke used to connect to each side rail to gang them together. Alatching mechanism is mounted on the floor of the ski. The yoke dependsdown into the inner contour of the ski and the bottom portion of theyoke latches into the latching mechanism.

It is important that the wheel unit be easily deployable by a person ofaverage strength. To deploy the wheel unit having a deployment mechanismthat includes a side rail and latching pin, the operator lifts the skiby the handle that is typically provided at the front end of the ski,grabs hold of the crossbar (if two side rails are ganged with acrossbar) or the latching pin, and slightly lifts and slides thecrossbar or the latching pin forward toward the front end of the skiuntil the it latches in the first or deployed position. This effectivelylowers the wheel or wheels and locks the wheel unit into place. Thesnowmobile is now drivable across gravel and hardtop surfaces withoutlosing its ability to be steered with the handlebars. To retract thewheels, the procedure is reversed. The operator lifts the ski until theweight of the snowmobile is off the wheels, grabs the crossbar orlatching pin and slides it toward the rear end of the ski until itlatches in the second or retracted position. The wheel or wheels are nowsecured in a raised or retracted position in which the lowest point ofthe wheels is above the gliding surface of the ski, allowing thesnowmobile to glide fully on the skis.

In some cases, it is desirable or necessary to mount the wheel unit onthe side wall or saddle of the ski, rather than on a kingpin. The sidewall-mount wheel unit is provided for this purpose. The side wall-mountwheel unit includes a mounting plate that is mountable on the side wallor on the saddle. The wheel-mounting bracket is mounted on a spindlethat extends from the mounting plate. As with the kingpin-mount wheelunit, either one wheel or a pair of wheels is mounted on each ski.Again, if a pair of wheels is mounted on the ski, a crossbar or someother means is ideally used to gang or link the two side rails, so thatmoving the deployment mechanism causes both side rails to movesimultaneously, thereby ensuring that the wheels are deployed/retractedsimultaneously.

A universal wheel unit according to the invention is provided that ismountable on virtually any conventional ski. The universal wheel unit ismountable on a kingpin mount, on the side wall, or on the saddle of aski and is particularly well-suited for mounting a single wheel on aski, rather than a pair of wheels.

It is within the scope of this invention to include an automaticallyactuatable wheel unit for ski-mounted vehicles. The deploymentmechanisms described above involve simple mechanical actuation. Anynumber of known automated or power-assisted means of actuating a cammechanism are suitable for deploying and retracting the wheels. In oneembodiment, the latching mechanism is spring-biased toward the retractedposition, so that, when the snowmobile weight is lifted from the ski,the wheel unit automatically shifts to a “retracted” position. Othermeans for actuating the deployment mechanism according to the inventioninclude such means as a pivot arm or linkage driven by an electricmotor, an electromagnetic means in which magnets are selectivelymagnetized to draw the deployment mechanism to a deployed or retractedposition, or hydraulic or pneumatic means. A small electric motor ismountable within the inner contour of the ski, for example, and thenwired to a thumb switch on the handlebar of the snowmobile. The motordrives a shaft that is connected to an arm that is pivotably linked tothe side rail or frame. When the shaft extends, the deployment mechanismis pushed to a deployed position, thereby lowering the wheels to anoperable level, and when the shaft retracts, it pulls the deploymentmechanism to a retracted position, thereby lifting the wheels above thelevel of the gliding surface of the ski. An indicator, for example, awarning light, connected either to the deployment mechanism or thepower-assisted actuating means, may be mounted on the dashboard or onthe handlebar to alert the operator when the wheel unit is deployed.

Although it is desirable that snowmobiles be sold already equipped withskis having a wheel unit according to the present invention, a wheel kitis provided for retrofitting a typical ski for any number of theconventional snowmobiles already available. In most cases, the skiitself need not be modified. When retrofitting a ski with a kingpin linkto receive the kingpin-mount wheel unit, the original kingpin may needto be replaced with a modified, longer kingpin, to which thekingpin-mount wheel unit is then attached. When retrofitting a ski thatdoes not have a suitable kingpin mounting assembly, or if a side-wallmounting is desired for other reasons, a sidewall-unit mounting plate iseither mounted over the double-scag fastening posts or fastened to theside wall or saddle of the ski; the wheel deployment mechanism and wheelassembly are then mounted on the plate. The universal wheel unit ismountable on the modified kingpin, on the side wall, over thedouble-scag fastening posts, or on the saddle of the ski, depending onthe type of ski. Regardless of which type of actuation means isinstalled, manual, electric, or other, a switch and/or an indicatorlight is retrofittable on the dash of the snowmobile.

With the wheel unit according to the invention, the wheels aresemi-permanently mounted on the ski. Depending on the particular travelconditions, the wheels are deployed, so that the snowmobile becomes awheeled vehicle, or retracted, so that the wheels are carried along sidethe ski in a raised position, above the gliding surface of the ski.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a conventional snowmobile ski (priorart).

FIG. 2 is a perspective view of a portion of a ski, showing a firstembodiment of the kingpin-mounted wheel unit according to the invention,and the deployment mechanism.

FIG. 3 is a perspective view of a ski according to the invention,showing the wheel unit of FIG. 2 in a retracted position, with themovable frame and a latching mechanism.

FIG. 4 shows a spring-biased movable frame according to the invention.

FIG. 5 shows a cross-section of the wheel unit of FIG. 2, showing themovable frame within the ski profile and a motor.

FIG. 6 shows in detail the wheel mount on the modified kingpin accordingto the invention.

FIG. 7 is a perspective view of a motorized wheel unit according to theinvention.

FIG. 8 is a partial view of a dashboard of a snowmobile, illustratingthe thumb switch to actuate the wheel unit according to the invention,and an indicator light to indicate that the wheels are deployed.

FIG. 9 shows a second embodiment of the kingpin-mounted wheel unitaccording to the invention.

FIG. 10 is a side view of the deployment mechanism of the wheel unit ofFIG. 9, showing the side rail and the wheel-mounting bracket.

FIG. 11 is a cross-sectional view of the wheel unit of FIG. 9, showingthe connections between the wheel-mounting bracket, the side rail, andthe kingpin.

FIG. 12 is a perspective view of an alternative embodiment of the wheelunit according to the invention, showing a side-wall-mounted wheel unitmounted on a double-scag type ski.

FIG. 13 is a side view of the side-wall mounting bracket, seated overthe fasteners for fastening carbides to the double-scag type ski, andalso showing the latching pin and the side-wall mounting holes formounting the wheel unit directly to the side wall of the ski.

FIG. 14 is an end view of the double-scag type ski, showing theside-wall mountable wheel unit mounted on the side wall of the ski.

FIG. 15 is an end view of a ski, showing the side-wall mountable wheelunit mounted on the side wall of the ski.

FIG. 16 is an end view of a ski, showing a mounting block for mountingthe wheel unit according to the invention integrated into the form ofthe ski.

FIG. 17 is an illustration of a side-wall mountable wheel unit accordingto the invention, with a schematically illustrated automated actuatingmeans mounted on the side-wall mounting bar and connected to theactuating end of the side rail.

FIG. 18 is an illustration of a biasing spring as the automatedactuating means of FIG. 17.

FIG. 19 is an elevational view of the universal wheel unit according tothe invention, as seen on the outside of the ski.

FIG. 20 is an elevational view of the universal wheel unit of FIG. 19,as seen on the inside of the ski.

FIG. 21 is a frontal view of the universal wheel unit of FIG. 19,illustrating the linking of the wheel cam, the universal rail, and thelatching mechanism.

FIG. 22 is a detail view of the modified universal rail for mounting onski scag posts.

FIG. 23 is a side view of the modified universal rail of FIG. 22.

FIG. 24 shows the universal rail mounted on the saddle of a conventionalski.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 shows a conventional snowmobile ski comprising a ski 1 having skisides 2, a lifting handle 3 disposed at a front end 1A of the ski, and areinforcing liner 6. A kingpin 5 is mounted in the ski 1. With theparticular ski shown, a spindle (not shown) mounts on the kingpin 5 toattach the ski 1 to the snowmobile. The present invention is a wheelunit that is mountable on the ski 1, and is either directly mountable onthe kingpin 5 or on a side 2 of the ski 1. It is noted here that areference designation assigned to a particular element of the inventionis maintained hereinafter throughout the description, even if theelement is used in more than one embodiment of the invention.

FIG. 2 shows an embodiment of a kingpin-mounted wheel unit 20 accordingto the invention that has been assembled on the ski 1. As shown in thisFIG. 2, the wheel unit 20 is in a deployed position. The wheel unit 20comprises a deployment mechanism that includes a movable frame 12 formedby two side rails 12A, 12B, a cross-bar 13 and a yoke 14, a modifiedkingpin 5A, a wheel mounting bracket 21, and a pair of wheels 18.Mounted in the bottom of the ski 1 is a latching means 15. In thisembodiment, the latching means 15 comprises a simple latch 16 and a stopplate 17. The movable frame 12 has been moved to a deployed position andthe yoke 14 is held by the latch 16.

FIG. 3 shows the wheel unit 20 in a retracted position. As can be seen,the movable frame 12 has been shifted toward a rear end 1B of the ski 1and the yoke 14 is held in position by the stop plate 17. Thisembodiment is a basic mechanical embodiment of the wheel unit 20 thatcan be deployed manually by a snowmobile operator. To deploy the wheelunit 20 from the retracted position shown in FIG. 3, the snowmobileoperator merely lifts up on the ski handle 3 with one hand, grabs thecrossbar 13 with the other hand and pushes it toward a front end 1A ofthe ski 20 until the yoke 14 catches under the latch 16 on the latchingmeans 15.

FIG. 5 shows a cross-section of the ski 1 with the wheel unit 20,looking from the rear toward the front of the ski 1. The movable frame12 is mounted on the ends of a modified kingpin 5A that extend to theouter side of the sides 2 of the ski 1. The kingpin 5A is longer thanthe conventional kingpin 5 to allow the movable frame to be mounted oneach of the kingpin 5A on the outside of each of the ski sides 2. A camor wheel-mounting bracket 21 is attached to each end of the kingpin 5A.Mounted eccentrically on each wheel-mounting bracket 21 is a wheel mountspindle 19 for mounting the pair of wheels 18. Due to the eccentricityof the mount, the wheels 18 are in a deployed position when the frame 12is moved into the deployed position toward the front end 1A of the ski 1and are in a retracted position when the frame 12 is moved toward therear end 1B of the ski 1. As shown in FIG. 3, the yoke 14 is positionedbehind the stop plate 17, with reference to the front end of the ski 1,and the wheel unit 20 is in a retracted position. As can be seen, thelowest point of each wheel 18 is raised above the gliding surface G ofthe ski 1.

FIG. 6 shows in greater detail the wheel cam or wheel-mounting bracket21 and the movable frame 12 according to the invention. Thewheel-mounting bracket 21 is rigidly and fixedly attached to a boss ateach end of the kingpin 5A. Extending eccentrically from the cam orwheel-mounting bracket 21 is a wheel mount spindle 19. The wheels 18 areattached by means of a bolt (not shown) to each side of the ski 1 thatis threaded into a threaded hole 22A in the spindle 19. The movableframe 12 is pivotably attached to the wheel-mounting bracket 21 asshown.

FIG. 4 shows a spring-biased embodiment of the wheel unit 20, comprisinga biasing spring 31. In this embodiment, the wheels are placed in thedeployed position manually, as described above; they are moved to theretracted position simply by lifting the weight of the snowmobile fromthe wheels. When the weight is lifted from the wheels, the spring-biasedyoke 14 is automatically pulled to the retracted position.

A motorized wheel unit 20A according to the invention is shown in FIG.7. The components of the motorized wheel unit 20A that are identical tothose of the wheel unit 20 have the same reference designation. Mountedon the bottom of the ski 1 is an electric motor M. The wiring for themotor is not shown herein, as it is well known in the art to connectelectrical devices in vehicles. A shaft S is fixedly connected at oneend to the motor M and pivotably linked at the other end to a first end13B of a pivot arm 13A. A second end 13C of the pivot arm 13A ispivotably linked to the crossbar 13 of the frame 12. When an actuationmeans 43 for the motor M is actuated, the shaft S is moved forwardtoward the front end 1A of the ski 1, causing the second end 13C of thepivot arm 13A to swing slightly up and in the direction toward the rearend 1B of the ski 1. Actuating the actuation means 43 while the shaft Sis in an extended position will cause the motor to retract the shaft S,thereby causing the frame 12 to move forward to a deployed position. Thedescription of this motor, shaft, and pivot arm is merely illustrative.Means of moving a rigid body back and forth are well known, and it isintended that the scope of this invention not be limited to a specificlinkage or actuating means.

FIG. 8 shows a dashboard 40 of a snowmobile. The actuation means 43 forthe motor M, which can be a thumb switch, a toggle switch, a buttonswitch, for example, is shown mounted on the handlebars 41 of thesnowmobile. An indicator light 42, shown here as mounted on thedashboard 40, indicates a deployed condition of the wheel unit.

FIGS. 9, and 9A, 10 show a second embodiment of the kingpin-mountablewheel unit 200, mounted on the kingpin 5 of the ski 1. This secondembodiment is very similar to the first embodiment with regard to theway the wheels 18 are mounted eccentrically on the cam or wheel-mountingbracket 21 on the ski 1, but has a modified deployment mechanism 212that includes two side rails 221, an anchor bar 222, and a crossbar 213that is connected at a connection point 213A to an actuating end 221A ofeach of the respective side rails 221. FIG. 9 is a top planar view ofthe wheel unit 200 and FIG. 9A is a partial cross-sectional view of theski 1 that shows the anchor bar 222 in greater detail. Thewheel-mounting bracket 21 and wheel 18 are not shown in FIG. 9A. Theanchor bar 222 is fixedly mounted on the ski 1 forward of the kingpin 5and has a locking pin 225 that extends from each end of the anchor bar222 outwardly from the respective side 2 of the ski 1. Although theanchor bar 222 can be mounted by any conventional means to the ski 1, itis practical with skis that have a carbide runner 111 attached to thebottom of the ski 1 to provide a through-bore in the anchor bar 222 andto use a fastener 111A as shown for attaching both the carbide runner111 and the anchor bar 222 to the ski 1.

See FIG. 10 for a side view of a portion of the ski 1, showing the sidewall 2, the wheel 18, and the side rail 221. A curved groove 223 forreceiving the locking pin 225 is provided in each side rail 221. Thecurved groove 223 has a first end 223A for latching the deploymentmechanism 212 in a deployed position in which the wheels 18 are incontact with the ground surface G and a second end 223B for latching ina retracted position in which the wheels 18 are raised above the groundsurface G. In the embodiment shown, the mechanism by which thedeployment mechanism 212 is locked into the deployed or retractedposition is very simple: the latching pin 225, once moved into thesecond end 223B, for example, does not release from this position untilthe crossbar 213 is lifted, thereby allowing the latching pin 225 todrop out of the latched position and move into the groove 223, alongwhich it slides until it latches into the first end 223A. FIG. 11 is aside view of the side rail 221 and the wheel-mounting bracket 19 andillustrates the linkage between the side rail 221, the wheel-mountingbracket 19, and the kingpin 5A. A rail pin 36 connects the side rail 221to the wheel-mounting bracket 19; a stub axle 34 is assembled in thewheel-mounting bracket 19 and rotatably supports the wheel 18; and thekingpin 5A is rotatably connected to the wheel-mounting bracket 19 by abolt end 32.

FIG. 12 is an illustration of an alternative embodiment of the wheelunit according to the invention. A side-wall-mountable wheel unit 300 ismountable on the outside of the ski, rather than on the kingpin 5, andcomprises a side-wall mounting bracket 304, the side rail 221 with thecurved groove 223, previously shown in FIG. 9, the wheel-mountingbracket 21, the wheel-mounting spindle 21, and a latching pin 306. Thealternative embodiment of the wheel unit according to the invention isparticularly advantageous for use with the conventional double-scag ski100 as shown in FIG. 12, or with skis without a suitable kingpinmounting. With the double-scag type ski 100, carbides are mounted on therunner surface of the ski 100 and are removably attached by means ofthreaded fasteners 110, such as bolts, as shown in FIG. 12. Thedouble-scag ski 100 has contoured side walls 302 with carbide-fastenerposts 303 integrated into the side wall construction. Thecarbide-fastener posts 303 have a bore for receiving the threadedfastener 110 that fastens the carbides to the runner of the ski 100. Theside-wall mounting bracket 304 seats against the contour of the sidewall 302 and is seated over the respective carbide fastener posts 303.The conventional threaded fastener 110 that is provided with the ski 100to fasten the carbide is replaceable with a longer threaded fastener, ifnecessary, and is used to fasten the side-wall mounting bracket 304 aswell as the carbide to the ski 100. A simple handle 311 may be used todeploy or retract the wheel unit 300, or an automated actuation meansthat is discussed below.

FIG. 13 is a side view of the side-wall mounting bracket 304 mounted onthe side wall 302 of the ski 100. As seen, the side-wall mountingbracket 304 has a first mounting end 304A and a second mounting end304B. Each of the mounting ends 304A/304B fits over a respectivecarbide-fastener post 303A/303B that extends upward from the side wall302. The through-bores 110A in the carbide-fastener post 303A/B areindicated by dotted lines. These through-bores 110A serve simultaneouslyfor attaching the side-wall mounting bracket 304 to the side wall 302.Additional mounting holes 307 for attaching the bracket 304 directly tothe side wall 302 are also shown, as is the latching pin 306, one end ofwhich is fixedly mounted on the side-wall mounting bracket 304 and theother end of which is captured in the curved groove 223 on the side rail221 when the wheel unit 300 is assembled. The side-wall mountable wheelunit 300 is also mountable on a ski that does not provide the threadedfasteners 110. In such a case, the side-wall mounting bracket 304 isattached to the outer side wall 302 by means of suitable fasteners thatare inserted through the mounting holes 307 and into bores that areprovided in the side-wall 302. A deployment mechanism 312 for thisalternative embodiment of the wheel unit 300 is similar to thatdescribed above and uses the same side rail 221. The latching pin 306that extends from the side-wall mounting bracket 304 is captured in thecurved groove 223 provided in the side rail 221.

FIG. 14 is a partial cross-sectional end view of the double-scag typeski 100, showing the completely assembled wheel unit 300 fitted againstthe contoured side wall 302 of the ski 100 and mounted to the side wallby means of the carbide fastener 110. The wheel-mounting bracket 19 ispivotably mounted to the side wall by a bolt 35 that is fastened in abore drilled directly into the sidewall 302. In this particular view,the wheel 18 is retracted.

FIG. 15 is an end view of the double-scag type ski 100, showing theside-wall mounting bracket 304 seated against the contour of the sidewall 302 and attached to the side wall 302 by means of threadedfasteners through mounting holes 307. This is an example of theversatility of the alternative embodiment of the wheel unit 300, whichis mountable on the double-scag type ski 100 by means of the fastenersthat are inserted and fastened in the through-bores 110A, or mountabledirectly onto the side wall 302 of the any ski that has a side wall bymeans of conventional fasteners that are inserted and fastened in themounting holes 307. If bores are not provided in the sidewall 302 of theski, they may easily be drilled into the sidewall 302 of the ski at theappropriate locations to receive the fasteners for the side-wallmounting bracket 304. Typically, threaded fasteners are used whenmounting the wheel unit 300 according to the invention, although it isincluded with the scope of the invention that any suitable fastener beused to mount the wheel unit 300 to the ski 100.

The side-wall mounted wheel unit 300 is preferably mounted on the ski inthe area of the kingpin mounting, as shown in FIGS. 12 and 13, becausethe section of ski where the kingpin is mounted is the balance point ofthe ski. The side-wall mounting bracket 304 shown in the illustrationsis one that is adapted to seat over the carbide fastener posts 303. Itshould be understood that a side-wall mounting bracket for mounting thewheel unit on a ski that does not have the carbide fastener posts in theside walls may have a simpler construction that allows it to be mountedagainst the side-wall. In other words, it is not necessary that theside-wall mounting plate have mounting ends that seat over carbidefastener posts, but only that the side-wall mounting bracket 304 seat upagainst and be attachable to the sidewall.

A further advantage of the side-wall-mountable wheel unit 300 as shownin FIGS. 1-15 is that it is semi-permanently attachable to theparticular ski. In other words, if so desired, it can be detached fromthe ski without impairing the ski. This is done simply by removingthreaded fasteners, removing the complete wheel unit 300, and, if thewheel unit had been attached with the carbide fasteners 110 in thethrough-bores 110A, re-fastening the carbides.

The embodiments of the wheel unit according to the invention shown thusfar have been separate wheel units that are mountable on conventionalskis. The scope of the invention also encompasses a ski that has a wheelunit integrated into its construction. FIG. 16 is an illustration of aski 500 which has a mounting block 503 for receiving a wheel assemblywith deployment mechanism. The mounting block 503 is molded into theside wall 502 of the ski 500. A wheel unit 600, comprising essentiallythe deployment mechanism 312 with at least one side rail 221 and alatching mechanism, the cammed wheel-mounting bracket 19, and a wheel18, is mounted on the mounting block 503. The wheel unit 600 isdetachably mountable to the mounting block 503 by means of a threadedfastener or other suitable fastening means. In another embodiment, thewheel unit 600 is permanently mounted on the mounting block 503 of theski 500.

FIGS. 17 and 18 illustrate an actuating means 38 that is rigidly mountedon a ski 400 on the side-wall mounting bar 304 and connected to theactuating end 221A of the side rail 221 by means of an actuating link39. Suitable conventional actuating means 38 for driving thewheel-deployment mechanism 212 of the kingpin-mountable wheel unit 200or the side-wall mountable wheel units 300 include an electric motorwith linkage to the side rail 221, a piston-and-cylinder assembly thatis connected to a pressurized fluid system, such as an hydraulic systemor a pneumatic system, or a biasing spring. FIG. 18 illustrates apossible mounting of a biasing spring 49 on a post 48, such that, whenthe ski 400 is lifted off the ground, the biasing spring 49 will urgethe side rail 221 toward a retracted-wheel position. Any number ofconventional actuating means are suitable for driving thewheel-deployment mechanism of the wheel unit of the present inventionand the description of an electric motor with linkage, a biasing springmechanism, or a pressurized-fluid system with piston and cylinder is notintended to limit the actuating means to these particular embodiments orconfigurations. Furthermore, the power source for driving the actuatingmeans is a conventional power source that is provided on the snowmobileand connected to the actuating means by conventional methods. Forexample, if the actuating means is a pneumatic system, the pressurizedair tank is mountable in any convenient and suitable location on thesnowmobile and connectable to the cylinder by means of a pressurizedhose. It is also known to mount an actuating switch in a convenientlocation on the snowmobile, for example, on the dash, and to connect itto the actuating means by conventional means, such as an electricsignal, an electromagnetic relay, an infra-red signal, etc.

In many of the illustrations, the particular ski is shown with theside-wall mounted wheel unit 300 mounted on only one side of the ski. Itshould be understood that the invention also encompasses mounting awheel unit 300 on each side of the ski. In such a case, it may bedesirable to modify the deployment mechanism 312 by providing a crossbarthat gangs the two ends of the side rails 221 together, similar to thecrossbar 213 shown above on deployment mechanism 212, so that the wheels18 are simultaneously deployed or retracted when the crossbar is moved.

FIGS. 19-23 illustrate a universal wheel unit 700 according to theinvention. The universal wheel unit 700 is a single-wheel unit that ismountable on virtually any conventional ski, with or without a kingpin.It comprises the wheel-mounting bracket 19 as described above, and adeployment and latching mechanism that includes a universal rail 702 anda latching device 704 with a spring-biased locking handle 712.

FIG. 19 shows the universal wheel unit 700 as seen from the outside of aski. The ski used in the illustration is the ski 1, which has a modifiedkingpin 5A. The universal rail 702 is mounted on the modified kingpin5A, between the ski side 2 and the wheel-mounting bracket 19. Theuniversal rail 702 is fixedly attached to the ski side 2 by means ofsuitable fasteners inserted through one or more of fastener bores 710.Suitable fasteners include threaded fasteners, rivets, bolts, etc. Afirst end of the latching device 704 is pivotably attached to thewheel-mounting bracket 19 by the rail pin 36 and a second end isattached to the locking handle 712, which is captured in a deploymentand latching groove 706. The latching groove 706 has a first end and asecond end, each of which is configured as a locking bore 708.

The spring-loaded locking handle 712, best seen in FIG. 21, is assembledat the second end of the latching device 704. The locking handle 712 isdimensioned such that it snaps into the locking bore 708 when alignedwith the bore. The handle 712, when pulled against the direction of thebiasing spring force, slides along a pin away from the universal railand allows the second end of the latching device 704 to be moved alongthe deployment and latching groove 706, in order to secure the handle712 in the other locking bore 708. By locking the locking handle 712 inthe first locking bore 708, the universal wheel unit 700 is secured inthe deployed position, in which the wheel 18 supports the weight of thesnowmobile, and by locking the handle 712 in the second locking bore,the universal wheel unit 700 is secured in the retracted position.

FIGS. 22 and 23 show a modified universal rail 702A that is adapted tomount the universal wheel unit 700 on double-scag type ski 100. Asshown, a scag-post adapter bar 714 is attached or integrally formed withthe universal rail 702. Bore holes 716 for receiving scag fasteners 110are provided in the scag-post mounting bar 704. This adapter bar 714allows the modified universal rail 702A to be mounted over the scagposts of the ski type shown in FIGS. 13-15. The bores 716 are spacedapart to receive the scag fasteners 110 of the conventional side wallski 100.

FIG. 24 is an illustration of a method of mounting the universal wheelunit 700 on the ski 400 that has a saddle 401. The kingpin mounting hole701 on the universal rail 702 is aligned with the kingping-mounting hole7 on the saddle 401. This assures that the universal wheel unit 700 ismounted at the balance point of the ski. The universal rail 702 is thenfastened to the saddle 401 by drilling one or more holes in the saddle401 such that they align with the corresponding fastener bores 710 onthe universal rail 702 and rigidly and securely fastening the universalrail 702 to the saddle with suitable fasteners.

Although the invention has been described with reference to severalspecific embodiments mentioned herein, these embodiments are merelyillustrative of the present invention. It should be understood thatnumerous variations in construction of the present invention may becontemplated in view of the following claims, without straying from theintended scope and field of the invention herein disclosed.

1. A wheel unit mountable on a ski of a ski-mounted vehicle, said skihaving a gliding surface for traveling over a ground surface and twoside walls, a first side wall and a second side wall, that extend upwardfrom said gliding surface and lengthwise along at least a portion ofsaid ski, and kingpin mounting holes, one in each of said side walls forreceiving a kingpin that is used to link said ski with said ski-mountedvehicle, said wheel unit comprising: a kingpin mountable in saidkingpin-mounting holes, said kingpin having a kingpin-end that extendsthrough a respective one of said kingpin-mounting holes to an outside ofsaid first side wall; a wheel-deployment device having a rail and alatching mechanism; and a wheel assembly that includes an eccentricallymounted wheel, wherein said wheel assembly is rotatably mountable onsaid kingpin end and shiftably linked to said rail.
 2. The wheel unitaccording to claim 1, wherein said wheel assembly comprises a wheelmounting bracket that includes a cam with a wheel-mounting spindle forrotatably mounting said wheel on said bracket, a spindle mount forrotatably mounting said bracket to said kingpin end, and a deploymentlink that shiftably links said wheel mounting bracket to said rail. 3.The wheel unit of claim 2, wherein said latching mechanism includes ananchor, a locking pin having a first pin end and a second pin end, and acurved groove in said side rail, said curved groove having a firstlatching position and a second latching position, and a wheel-deploymentactuating mechanism; wherein said locking pin is fixedly attached tosaid anchor by said first pin end and is slidably captured at saidsecond pin end in said curved groove and wherein, when saidwheel-deployment actuating mechanism is actuated, said locking pin andsaid rail cooperate so as to allow said wheel-deployment device to shiftsaid wheel-mounting bracket between a deployed-wheel position and aretracted-wheel position.
 4. The wheel unit of claim 3, wherein saidsecond end of said locking pin is slidably movable along said curvedgroove and lockable respectively in said first locking position at saiddeployed-position latching end and in said second locking position atsaid retracted-position latching end.
 5. The wheel unit according toclaim 3, wherein said rail has an actuating end and saidwheel-deployment actuating mechanism is a handle that is mounted at saidactuating end of said rail and is grippable.
 6. The wheel unit accordingto claim 3, wherein said wheel-deployment actuating mechanism is amechanical means having a first end fixedly attached to said ski and asecond end linked to said actuating end of said rail so as to urge saidwheel-deployment device toward said retracted-wheel position.
 7. Thewheel unit according to claim 6, wherein said mechanical means includesa biasing spring.
 8. The wheel unit according to claim 3, wherein saidwheel-deployment actuating mechanism is an electrical means having anelectrical drive means at said first end fixedly attached to said skiand a linkage that extends from said drive means and is linked to a saidactuating end of said rail.
 9. The wheel unit according to claim 3,wherein said wheel-deployment actuating mechanism is a pressurized-fluidsystem having a cylinder fixedly attached to said ski and a retractablepiston that extends from said cylinder and is attached to said actuatingend of said rail so as to move said wheel-deployment device between saiddeployed-wheel position and said retracted-wheel position.
 10. The wheelunit according to claim 9, wherein said pressurized-fluid system is ahydraulic system.
 11. The wheel unit according to claim 9, wherein saidpressurized-fluid system is a pneumatic system.
 12. The wheel unitaccording to claim 3, wherein said wheel-deployment actuating mechanismis automated and includes a switch mountable in an area of said vehiclethat is readily accessible to an operator of said vehicle and that sendsa signal to said wheel-deployment actuating mechanism that causes saidwheel-deployment device to move between said retracted-wheel positionand said deployed-wheel position.
 13. The wheel unit according to claim1 further comprising a wheel-unit indicator that indicates said deployedposition of said wheels, wherein said ski-mounted vehicle has adashboard and said indicator is mountable on said dashboard andconnectable to said wheel unit.
 14. The wheel unit according to claim 1,wherein said rail has an actuating groove with a deployed-lockingposition at a first end and a retracted-locking position at a second endof said groove, wherein said latching mechanism includes a spring-biasedbar that snaps alternately into said deployed-locking position or saidretracted-locking position to secure said wheel assembly respectively ina deployed position or a retracted position.
 15. The wheel unitaccording to claim 14, wherein said rail includes one or more bores formounting said rail on said side wall.
 16. The wheel unit according toclaim 14, wherein said rail includes a scag-post mounting bar with boresfor receiving carbide fasteners.
 17. A ski for use with a ski-mountedpower vehicle, said ski comprising: an inner bottom ski surface,kingpin-mounting holes for connecting said ski to said ski-mounted powervehicle; ski side walls that extend upward from said inner bottomsurface, a wheel unit according to claim 1 mounted on a kingpin thatextends through said kingpin-mounting holes.